Concurrency that reads like your intent.
Actors, channels, and structured scopes are part of the language—not a library bolted on later.
Siyo 0.3.1 is out
Concurrency on the JVM.By Design.
Safe and simple by default. Siyo is a compiled language with actors, channels, and native Java interop. Familiar enough to start today. Different enough to enjoy it.
Bundled runtime · No Java installation required
actor Store { data: map } impl Store {fn new() -> Store {Store { data: map() }} fn set(self, key: string,value: string) -> string {self.data.set(key, value)"OK"}} mut store = spawn Store.new()println(store.set("lang", "siyo"))›siyoc run store.siyoOK
Direct bytecode
JJava 21+
19K+lines of compiler
1,475automated tests
37built-in functions
2execution backends
Why SiyoSmall language.
Small language.
Serious machinery.
Designed around the way software is built now: concurrent by default, connected to an enormous ecosystem, and pleasant to read six months later.
Bytecode, directly. No translation layer.
Siyo emits standard JVM bytecode and runs beside Java and Kotlin with access to the full ecosystem.
Modern ideas, without ceremony.
Closures, pattern matching, structs, interpolation, and typed functions in one compact syntax.
The languageReadable on Monday.
Readable on Monday.
Powerful on Friday.
Siyo keeps the syntax compact while giving you real tools for real systems. Build APIs, model data, coordinate work, or call Java when you need to.
Pattern matching
Structs & enums
Closures
Actors
Channels
Java interop
actor Counter { value: int }
impl Counter {
fn increment(self) -> int {
self.value += 1
self.value
}
}
mut counter = spawn Counter { value: 0 }
println(toString(counter.increment())) Under the hoodOne frontend.
One frontend.
Two ways to run.
The compiler and interpreter share the same analysis pipeline, so compiled programs and debug runs keep identical semantics.
01LexerTokens
02ParserSyntax tree
03BinderTypes & names
04LowererControl flow
EmitterJVM bytecode
EvaluatorInterpreter
ASM backend emits standard .class files
Virtual threads power lightweight concurrency
Parity tests compare both execution paths
Start buildingFrom zero to running
From zero to running
in one command.
Install Siyo with its bundled runtime, then create your first project.
curl -fsSL siyolang.org/install | sh01
Windows and source installation siyoc new my-app02cd my-app03siyoc run One language, wide reach
Build past the demo.
Siyo already ships with the pieces to explore real applications.
Make something
unexpected.
Siyo is young, public, and ready for curious builders.